Hard disk light always remains on

I just purchased a SanDisk Extreme 240GB solid state drive and installed it to my Pentium 4, SATA1 machine.

I noticed that once Windows has booted up and loaded, the PC’s hard disk light remains constantly on.  It will never blink on or off after Windows has booted.  Is this normal?  This is the only drive (other than the DVD) in the PC.